Newly discovered regulatory aspects of metabolism will be studied. This includes: (a) dehydrogenation of amino acids, such as aspartate, tyrosine, and alanine, by the enzyme-enzyme complex of transaminase and glutamate dehydrogenase; (b) investigations of the metabolic importance of the keto group and pyridine nucleotide binding site on heart transaminase on preservation or maintenance of transaminase as an active enzyme and energy metabolism of the heart; (c) studies of the possibility that heart transaminase forms enzyme-enzyme complexes with dehydrogenase important in heart metabolism as it is known to with glutamate dehydrogenase, cystathionase and a specific proteinase; (d) exploration of the known role of drugs and mitochondrial phospholipids on these systems. The above studies are important in energy, amino acid, and catechol amine metabolism in heart, liver, and brain. The complex between transaminase and glutamate dehydrogenase might be a major pathway for amino acid metabolism. This study is important in states such as starvation, hepatic coma, and gout and in the energetics of the failing heart.